Vector Capital, a San Francisco buyout firm, has raised its fourth fund, totaling more than $1.2 billion.

The firm's previous fund, totaling $350 million, was raised in 2005 before the latest onset of the buyout boom, which has seen firms amass ever larger amounts of capital. They're buying out companies, taking them private and then hoping to sell or take them public again for a profit.

Asked why he is raising so much capital, Partner Alex Slusky said he didn't think it was that much given the opportunities available. Vector also raised more money to avoid the need for Vector's investors to co-invest along side Vector in its bigger deals.

He said Harvard University is a new investor.